Deformation
MM43, presume the empennage slowed rapidly on contact, rest of structure carries on progressively being decelerated, rear fuselage shears early on owing to the differential accelerations with VS detaching some time in the sequence owing to differential accelerations between it and the (residual) fuselage. Rear section then sinks taking its witness marks and downward twisting with it. Are there any signs of compression at the base of the VS ?